Electrophoretic variation of enzymes of malaria and babesia parasites is being studied by starch gel electrophoresis. Material for the study of the human malaria parasites P. vivax and P. falciparum has been collected and is stored ready for examination. An expedition to the island of Nantucket has been planned for the collection of isolates of babesia from rodents. Isolates of human babesia are already stored ready for examination. Four enzymes have been found to be suitable for the study of enzyme variation in malaria parasites and two are suitable for study in babesia.